Radial piston machine

Abstract

In a radial piston machine, there is provided an outer stator and an inner rotor rotatable on a control pintle provided with supply and discharge channels. The rotor contains at least one radial bore in which is slidable a spherical piston comprising an outer ball and an inner cylindrical sleeve. The radially inward end of the sleeve, which end is adapted to be acted upon by the outlet pressure of the machine, includes a sealing lip which, during operation, in particular at higher pressures, expands circumferentially and, under certain circumstances, moves in sealing abutment with the inner wall of the radial bore.

We claim: 
     
       1. A radial piston machine for transmitting fluid therethrough, said machine comprising a stator, a rotor disposed in said stator and rotatable on a stationary control pintle having supply and discharge channels, a radial through-bore in said rotor adapted for periodic connection to said supply and discharge channels, said through-bore containing a first and a second radially displaceable spherical piston disposed at opposite ends of the bore on opposed sides of the control pintle, each piston including a radially outwardly disposed ball seated in a radially inwardly disposed unitary cylindrical sleeve, with each piston radially slidable relative to a cam surface on said stator, each said sleeve comprising a cylindrical outer wall of uniform diameter and circumference each sleeve including an axially concentric through passage having a conic seat for its associated ball at one end to provide a line contact therewith, and in which said passage bounds an outwardly tapering wall of said sleeve at the other end of said sleeve forming a peripheral integral sleeve lip positioned to sealingly engage the adjacent bore wall with a gap sealing lip responsive to pressure above a predetermined level passing through said passage.